During the decade beginning in 2000, the copper damascene process became the dominant IC fabrication technology employed to form metal interconnects. In the damascene process, a dielectric layer is patterned to provide recessed features defining the locations of interconnect lines and/or vias. These features are then conformally coated with a thin layer of diffusion barrier material such as tantalum nitride. Subsequently conductive copper is electroplated into the patterned features to form conductive lines and vias.